Rotary tillage tool



` March 5, 1940. LDUFQUR 2,192,342

ROTARY TILLAGE ToorJ Filed Aug. l0, 1957 Patented Mar. S, 1940 PATENT orner:A

' ROTARY TILLAGE Toor.

Lon Dufour,` Acacias-Geneva, Switzerland Application August 10,

1937, Serial No. 158,443

In Germany .lune 30, 1937 13 Claims.

Spring arrangements, forme-d by long spirally wound spiral springs, for the tools of motor operated machines for working the soil, wherein the tooll itself forms a part of -the spring or is 6 secured thereto are known.

These springs are frequently distorted or broken by reason of the strains to which they are subjected during operation. In order to remedy this defect endeavours have already been made to mount the tool, secured to the spring, rotatably about the axis of the spring so that radial strains are taken up by this axis yoi? rotation. In this manner distortions are obviated but not the breaking of the springs which always occurs.

Careful investigation has now shown that these breakages are due to the fact that the inner part subjected to pressure when tensioning the spring, for example when the tool meets an obstruction, is subjected to tensioning to a far-reaching extent on the sudden expansion, after the obstruction has been overcome resulting from the mass of the tool connected to the spring. For

due to the inuence ci the mass of the tool connected to the spring. The spring breakages which so frequently occur are also very probably due to vresonance phenomena. When for example a tool during its oscillation about its normal position meets vwith an obstruction, just when it is located at the end of an oscillation, by which the spring is already tensioued, this is subjected to an excessive strain, which may cause a breakage, in consequence of the resultant additional tensioning.

The present invention relates to an arrangement of a, tool in combination with a longitudinally spirally wound spiral spring, according to which the tool only acts on the spring in one direction and is freely movable in the opposite direction so that on relaxation kof the spring this is not inuenced by the movement of the tool.

A form of construction of the subject of the invention is shown by way of example in the accompanying drawing, wherein: Fig. 1 shows a side elevation. Fig. 2 shows a plan partly in section. Fig. 3 is a fragmentary top plan viewer-a` modified form of the construction, and

Fig. 4 is a Vertical sectional View taken on the line 4l-1l of Figure 3.

The main shaft IU carries a holder Il with two apertured lugs 25 for the reception of the ends ll of the longitudinally spirally wound spiral I spring l2.

At the middle portion the spring l2 forms an elongated loop lli of which the middle portion lll serves as a stop for the tool I5 which is normally freely movable in the loop. The two tends l@ of the loop approach one another at an acute angle and then extend parallel to one another for a predetermined length I9 so that in the direction thereof they may prevent a movement oi the tool resiliently and then with a constant braking action.

On each end Il of the spring l2, which projects irom the lugs 25 of the holder Il, there is fitted an arm I8 provided with a corresponding hole.

Each arm I8 is bent at an angle so that its free end lies transversely to the central axis oi the spring l2. At this central axis each arm carries a bearing 23 for a tool-shaft 2li about which the tool is mounted rotatably. In addition v2(5 cylindrically-shaped jaws 2l are provided on both sides of the bearings 23, these jaws engaging the spring l2. The tool-shaft 20 is prevented from rotation and axial movement by pins 22. The assembly of the parts above described is effected 3oI simply by tting the arms I8, whilst located parallel to the main-shaft Hl, on the ends l'l of the spring .andv then turning them through so that the jaws 2| enter the interior of the spring. After the tool-shaft 2!) has been fitted 35 into the bearings 23 relative movement of the arms it and the spring l2 is no longer possible.

l As will be seen from the drawing the whole arrangement is held together solely by the pins 22.

The method of operation of this spring ar- 40" rangement is as follows:A

The tool l5, which is capable of rocking about the tool-shaft 2li and is freely movable in the spring loop l 3, normally bears against the midelle part l@ of the latter, position shown at A 45 in Fig. 1.

When during normal operation of the implement the tool rotating in the direction of the arrow 24 meets an obstruction, for example on the soil which is to be treated, the Spring yields and is tensioned to its full extent so that the tool for example reaches the position B. lWhen the obstruction has been overcome, that is to say for example when the tool during its rotation passes out of the ground, the spring l2 expands 55 suddenly and naturally moves the tool I5 with it. As, however, the latter moves freely in the loop I3 its mass has no influence on ther spring I2 so that the spring returns into its normal position immediately and without any separate strain. The tool, however, continues to move in the loop I3 until it meets the approaching ends I6 thereof which apply a resilient stopping action thereon (position C). When the tool enters the space between the two parallel parts I9 of the spring I2, it forces them apart and thereby is continuously braked until its movement ceases. In other words the impact of the tool is transmitted through the spring I2 to the holder I I and thereby is absorbed without shock.

By this arrangement the spring I2, during its expansion, is prevented from being subjected in its internal part by a substantial tensional strain, and thus damaged, by the mass or" the toolacting thereon.

Because the kinetic energy of the tool is no longer transmitted to the spring but only its degree of velocity in consequence of the impact on the parts i6. This is absorbed comparatively slowly by the resilient braking action of the parts I9. The resultant stressing or tensioning of the spring is extremely small and thev question of resonance phenomena no longer arises.

According to the alternative `embodiment of the invention illustrated in Figs. 3 and 4, the construction is the same as illustrated in Figs. l and 2 with the exception that the loop 31 of the spring IZb is open at its forward end to permit'iree forward or return movement of the tool I 5b, and with the further exception that, in lieu of constricting the forward end of said loop, as in Figs. 1 and 2, two spring arms 25 are mounted on lugs 2d carried by the holder IID and are disposed to have the tool enter therebetween 'during its return or forward swinging movement, whereby its said movement is resiliently arrested independently of the spring |210.

1. In a spring arrangement for the tools of motor operated machines for working the soil, the combination comprising a main-shaft, a tool-shaft parallel to the main-shaft, a tool rotatably mounted on said tool-shaft, a spiral spring coiled longitudinally around said toolshaft, said spring beingsecured at least at one end thereof to the main-shaft, said spring operatively engaging said tool in one direction of rotation, said tool being adapted to move independently of said spring in the opposite direction of rotation,

2. In a spring arrangement for the -tools of motor operated machines for working the soil, the combination comprising a main-shaft, a tool-shaft parallel to the main-shaft, a tool rotatably mounted on said tool-shaft, a spiral spring coiled longitudinally around said toolshaft, said spring being secured at least at one end thereof to the main-shaft, an elongated loop formed in said spring, said tool engaging with said loop, the arrangement being such that on rotation of lthe shaft in one direction said loop engages said tool, whilst in the opposite direction of rotation said tool moves freely in said loop.

3. In a spring arrangement for the tools of motor operated machines for working ythe soil, the combination comprising a main-shaft, a toolshaft parallel to the main-shaft, a tool rotatably mounted on said tool-shaft, a spiral spring coiled longitudinally around said tool-shaft, said spring being secured atleast at one end thereof to the main-shaft, a loop formed at the middle of said spring, said loop havingtwo parallel sides which tool moves away from the' closed end ofthe loop f the inclined portions of the loop act: as a resilient stop for the tool and the spaced. parallel sides extending from the inclined-'portions apply a braking action to the tool.

4. In a spring arrangement for the tools of motor operated machinesl for working the soil,

the combination comprising a main shaft, a tool-shaft parallel to the main-shaft, a tool rotatablymounted on said tool-shaft, a spiral spring coiled longitudinally around said' toolshaft, said spring operativelyl engaging said tool in one direction of rotation, said tool being adapted to move` independently of said spring in the opposite direction of rotation, arms secured to the main-shaft, the ends of said spring being secured to said arms. f

5. In a spring arrangement for theftools of motor operated machines for working the soil, the combination comprising a main shaft, a tool-shaft parallel to the main-shaft, a tool rotatably mounted on said tool-shaft, a spiral spring coiled longitudinally around said toolshaft, said spring operatively engaging said tool in one direction of rotation, said` tool being adapted to move independently of said spring in the opposite direction of rotation, arms secured to the main-shaft, the ends of said spring being secured to said arms, and the tool-shaft' being supported from said arms.

6. In a spring arrangement for the tools of lugs located on said holder, a spiral spring surrounding said tool-shaft, the ends of'said spiral spring engaging said apertured lugsfsaid endsl projecting from said lugs, a pair of arms mounted one on each extending' end of said spring,-a pair of bearings located one in each arm, a toolshaft mounted in said bearings, said tool-shaft extending through said spring, jaws onsaid arms, said jaws engaging with the opposite ends of said spring, means preventing said tool-shaft from rotating or moving axially in said bearings, a loop in said spring, and a-tool rotatably mounted on said tool shaft and engaging said loop.

'7. In a spring arrangement for the. tools of motor operated machines for working the soil, the combination comprising a main-shaft, av tool-shaft parallel to the main-shaft, a holder secured to said main-shaft, a pairof apertured lugs located on said holder, va spiral spring surrounding the tool-shaft extending longitudinally to the said main-shaft, the ends of said spiral spring engaging said apertured lugs, `said ends said spring, jaws on said arms, said jaws engaging with the opposite ends of said spring, means preventing said tool-shaft from rotating or movinwhich jaws are provided on said armsto enter ing axially in said bearings,a loop in saidspring,

vand a tool rotatably. mounted on said tool-shaft and engaging said loop. l

l8. A spring arrangement according to claim 6, wherein the loop has parallel sides and is closed at one end, the other ends of the parallel sides approaching one another at an acute angle and then extendingl parallel to one another in spaced relation.

9. In a spring arrangement for the tools of motor operated machines for working the soil, the combination comprising a main-shaft, a tool-shaft parallel to the main-shaft, a tool rotatably mounted on said tool-shaft, a spiral spring coiled longitudinally around said toolshaft, said spring being secured at least at one end thereof to the main-shaft, said spring operatively engaging said tool in one direction of rotation, `said tool being adapted to move independently of said spring in the opposite direction of rotation, a stop secured to the main-shaft to limit the movement` of the tool in said last direction.

10. The combination as set forth in claim 1 in which arms for supporting the tool shaft are pivoted to the holder for swinging movements between operative and inoperative positions, and

the ends of the spring when said arms are swung to their operative positions.

11. The combination as set forth in claim 1 including a resilient abutment separate from the springto arrest movement of the tool when the latter moves independently of the spring.

12. The combination as set forth in claim 1 in which arms for supporting the tool `shaft are pivoted on the ends of the spring projecting from the holder for swinging movements between operativeand inoperative positions,` and in which jaws are provided on said arms to enter `the ends of the spring when said arms are swung to their operative positions for supporting the ktool shaft.

13. In a rotary tillage tool, the combination,

single coil spring having one end thereof fitted i in said opening of the lug, said spring having an integral loop in the coiled portion thereof for receiving the shank of the tool.

LoN DUFOUR. 

